Turbine ventilators are widely used for under-roof ventilation in domestic, commercial and industrial applications. Their popularity stems largely from a relatively modest purchase cost coupled with a substantial absence of any operating cost and ability to operate without regulation. That is, the primary purpose of the turbine ventilator is to exhaust under-roof accumulation of hot air either internally generated or as a result of sun load on the roof. For that purpose, a precise quantity of airflow need not be maintained continuously but can instead be permitted to fluctuate within a wide range.
Being wind-powered, capacity fulfillment of the turbine ventilator to induce a forced airflow upward through a roof opening is dependent upon and will fluctuate extensively in correlation to ambient wind velocity. Continuous exposure to varying wind and rotational forces subjects the ventilator and its bearing supports to severe vibration and wear.